Systems doing data communication from a peripheral device or client device to a host device with current modulation on a voltage supply line are well-known and widely used. Such systems are using the fact that the supply line has a constant voltage, such that a fast and non-interrupted bit stream can be sent by modulating the current on the supply line. A performance of such data transmission is better in the case of current modulation pulses being larger than, for instance AC components of a supply current determined by other components connected to the supply line.
It may be desirable not only to transmit information from the client side to the host side but also to transmit information in the other direction.